Blacus ( Blacus ) adustiabdominus, Lu & Chai & Achterberg & Tang & Chen, 2024

Blacus ( Blacus) adustiabdominus sp. nov.

( Figs 1–2 View FIGURE 1 View FIGURE 2 )

Material examined. Holotype: ♀, China, Fujian, Wuyi Mtn, Xingcun Town , 20.IV.2009, Tan Jiangli, No. 201605131 ( ZJUH) . Paratypes: 3♀♀, China, Guangdong, Shixing, Chebaling, 19.IV.2002, Xu Zaifu , Nos. 20050568, 20051005; 21.VIII.2003, Xu Zaifu, No. 20052130 ( ZJUH) .

Description. Female. Length of body 1.9 mm, length of fore wing 2.0 mm.

Head. Antennomeres 17, slender ( Fig. 2C View FIGURE 2 ); length of first flagellomere 1.1 × length of second flagellomere; length of first, second and penultimate flagellomere 4.8, 4.0 and 1.6 × their width, respectively; maxillary palp 1.1 × height of head; occipital carina complete ( Fig. 2A View FIGURE 2 ); frontal suture present; OOL: OD: POL = 7: 2: 5; length of eye in dorsal view 0.9 × length of temple; face smooth ( Fig. 2B View FIGURE 2 ); malar suture absent, length of malar space 1.75 × basal width of mandible.

Mesosoma. Length of mesosoma 1.5 × its height; side of pronotum rugose ventrally, smooth dorsally ( Fig. 2D View FIGURE 2 ); precoxal sulcus complete, wide and reticulate-rugose ( Fig. 2D View FIGURE 2 ); notauli complete and narrow, nearly smooth ( Fig. 2E View FIGURE 2 ); mesoscutal lobes glabrous ( Fig. 2E View FIGURE 2 ); scutellum largely smooth, its lateral carina complete, not protruding apically; propodeal tubercles absent; surface of propodeum reticulate-rugose, medial area absent ( Fig. 2F View FIGURE 2 ).

Wings. Fore wing: parastigma slightly differentiated from vein C+SC+R, first discal cell acute anteriorly; vein 3-SR+SR1 of fore wing nearly straight; vein CUla of fore wing nearly at same level as vein 2-CU1; 1-CU1: 2-CU1 = 1: 4; vein 2-M absent ( Fig. 2I View FIGURE 2 ).

Legs. Hind coxa slightly rugose; hind femur swollen apically, length of femur, tibia and basitarsus of hind leg 4.6, 12.5 and 9.5 × their width, respectively.

Metasoma. Length of first tergite 1.7 × its apical width, widened apically, reticulate-rugose ( Fig. 2G View FIGURE 2 ); remainder of tergites smooth ( Fig. 2G View FIGURE 2 ); length of ovipositor sheath 0.21 × length of fore wing, 1.1 × length of hind femur, 0.7 × length of hind tibia.

Colour. Dark reddish-brown; base of antenna, clypeus, mandible, palpi, tegulae, pterostigma, parastigma, veins and all legs yellow; side of pronotum, metasoma (except first tergite), ovipositor and sheath brown; wing membrane infuscated.

Variation. Length of first metasomal tergite 1.7–1.8 × its apical width; length of fore wing 1.9–2.0 mm; length of ovipositor sheath 0.21–0.22 × length of fore wing; side of pronotum yellowish-brown to brown.

Male. Unknown.

Biology. Unknown.

Distribution. China ( Fujian, Guangdong).

Etymology. The specific name adustiabdominus refers to the brown metasoma and is derived from “ adustus ” (Latin for brown) and “ abdomen ” (Latin for abdomen).

Notes. The new species is similar to B. ( B.) inopinus van Achterberg, 1976 because parastigma is small and narrow, slightly differentiated from vein C+SC+R, first discal cell of fore wing acute anteriorly, scutellum largely smooth, ovipositor sheath somewhat longer than hind femur, vein CUla of fore wing nearly at same level as vein 2-CU1, vein 2-M of fore wing absent, propodeal tubercle absent, length of first metasomal tergite 1.7 × its apical width, and malar space longer than basal width of mandible, but differs by having narrow and nearly smooth notauli (wide and distinctly crenulate in B. ( B.) inopinus ), posterior surface of propodeum less reticulate (more reticulate), antenna equally wide overall (narrowed medially and widened apically), length of malar space 1.75 × basal width of mandible (1.2 ×), and length of ovipositor sheath 0.21–0.22 × length of fore wing (0.27 ×).